Hi all -- it's been a long time since I've participated in this group. I've been lurking for a few days, and am very pleased with the quality of the posts that I've read! It's good to see that this discussion continues!
Some comments below. Tim May wrote: > > On Monday, July 8, 2002, at 03:40 PM, Hal Finney wrote: > >> Future uncertainty is familiar to us, but one of the things that the >> many universe model introduces is past uncertainty. There is a sense >> in which the past is not unique and determined. My mental state is >> consistent with many macroscopically distinct pasts. I like this concept quite a lot. It's esthetically pleasing -- treating the past and the future more symmetrically than usual. > > > I'm not convinced that this is so. Sure, there are many views of past > events, of history, faulty memories, changing memories, etc. > > However, the "single past" model is quite well-supported by science and > a kind of "convergence" of knowledge: Do you know that this is so -- that the "single past" is supported to the exclusion of the "multiple past" concept? > .... > I agree that many possible causal pasts lead up to what you are. The > placement of grains of sand on a beach in Greece is not going to > significant affect who you are right now, so this is just one of a vast > multitude of possible causal pasts which will not affect your currrent > mental state. > > But this does not mean these possible pasts have equal "actuality." For > example, two different observers may have carefully photographed the > patch of beach where the possible variations occurred. The more accurate > their observations or photographs are, the more closely they will agree > on what that past was (again, assuming honest observers). Ah, but you missed the point, I think. Even if those grains have been observed by other humans, they still haven't been observed by *me*. My present mental state is consistent with lots of different possibilities with regards to position of the grains of sand, *and* to the observation or non-observation, *and* to the meta-observation, etc. Think Schroedinger's cat. > Nothing in science points to the "many actual pasts" possibility, even > though I acknowlege your point that "many _possible_ pasts" would lead > to a indistinguishable equal mental state for you or me. I *think* that this topic is treated in Victor Stenger's "Timeless Reality". Has anyone read it? I started it, but as often happens, I got distracted before I finished it. > > In other words, science points to a single actual past. There is, so > far, no evidence for multiple actual paths. > --- [This E-mail scanned for viruses by friend.ly.net.]
